MAUI在OSX（Mac Catalyst）调用CapturePhotoAsync出现黑屏问题

在Android模拟器中调用MediaPicker.Default.CapturePhotoAsync()能正常显示模拟相机视图，但在Mac Catalyst（OSX）环境下执行同一代码时，仅显示黑屏，相机按钮呈暗红色且无法点击。已按官方文档配置Info.plist权限，MAUI版本试过9.0.90及其他9.0.x旧版本。

调用代码 #

var photo = await MediaPicker.Default.CapturePhotoAsync();

已配置的Info.plist权限 #

<key>NSCameraUsageDescription</key>
<string>This app needs access to the camera to take photos.</string>
<key>NSMicrophoneUsageDescription</key>
<string>This app needs access to microphone for taking videos.</string>
<key>NSPhotoLibraryAddUsageDescription</key>
<string>This app needs access to the photo gallery for picking photos and videos.</string>
<key>NSPhotoLibraryUsageDescription</key>
<string>This app needs access to photos gallery for picking photos and videos.</string>

排查及解决步骤 #

• 检查Mac系统权限
  打开系统设置 → 隐私与安全性 → 相机，确认你的MAUI应用已被授予相机访问权限。即使Info.plist配置正确，系统层面可能未授权。若未找到应用，可先删除应用重新部署，触发权限请求弹窗后选择允许。

• 验证权限配置准确性
  确保Info.plist中的NSCameraUsageDescription描述清晰准确，Mac Catalyst对权限描述的要求和iOS一致，不能留空或模糊。

• 替换为原生相机实现（临时方案）
  若官方MediaPicker在Mac Catalyst上存在兼容性问题，可尝试使用NSCameraCaptureSession原生实现拍照功能，示例代码如下：

  #if MACCATALYST
  using AVFoundation;
  using Foundation;
  using UIKit;
  
  public async Task<string> CapturePhotoNative()
  {
      var captureSession = new AVCaptureSession();
      captureSession.SessionPreset = AVCaptureSession.PresetPhoto;
  
      var cameraDevice = AVCaptureDevice.GetDefaultDevice(AVMediaType.Video);
      if (cameraDevice == null) return null;
  
      var input = await AVCaptureDeviceInput.FromDeviceAsync(cameraDevice);
      if (input == null) return null;
  
      if (captureSession.CanAddInput(input))
          captureSession.AddInput(input);
  
      var output = new AVCapturePhotoOutput();
      if (captureSession.CanAddOutput(output))
          captureSession.AddOutput(output);
  
      captureSession.StartRunning();
  
      var photoSettings = AVCapturePhotoSettings.FromFormat(output.AvailablePhotoPixelFormatTypes[0]);
      var tcs = new TaskCompletionSource<string>();
  
      output.CapturePhoto(photoSettings, new PhotoCaptureDelegate(tcs));
      var photoPath = await tcs.Task;
  
      captureSession.StopRunning();
      return photoPath;
  }
  
  private class PhotoCaptureDelegate : AVCapturePhotoCaptureDelegate
  {
      private readonly TaskCompletionSource<string> _tcs;
  
      public PhotoCaptureDelegate(TaskCompletionSource<string> tcs)
      {
          _tcs = tcs;
      }
  
      public override void DidFinishProcessingPhoto(AVCapturePhotoOutput output, AVCapturePhoto photo, NSError error)
      {
          if (error != null)
          {
              _tcs.SetException(new Exception(error.LocalizedDescription));
              return;
          }
  
          var data = photo.FileDataRepresentation;
          var tempPath = Path.Combine(Path.GetTempPath(), $"photo_{Guid.NewGuid()}.jpg");
          File.WriteAllBytes(tempPath, data.ToArray());
          _tcs.SetResult(tempPath);
      }
  }
  #endif
  

  使用时直接调用CapturePhotoNative()替代MediaPicker.Default.CapturePhotoAsync()即可。

• 更新版本或反馈问题
  尝试升级到MAUI最新稳定版（如9.0.100+），看是否已修复该兼容性问题。若问题仍存在，可向MAUI官方仓库提交Issue，附上详细环境信息和复现步骤。

内容的提问来源于stack exchange，提问作者LosManos